don't delete RouterInfo's buffer right a way

libi2pd/NetDb.cpp

@@ -646,6 +646,11 @@ namespace data
 		for (auto& it: m_RouterInfos)
 		{
 			if (!it.second || it.second == own) continue; // skip own
+			if (it.second->IsBufferScheduledToDelete ()) // from previous SaveUpdated, we assume m_PersistingRouters complete
+			{
+				std::lock_guard<std::mutex> l(m_RouterInfosMutex); // possible collision between DeleteBuffer and Update
+				it.second->DeleteBuffer ();
+			}	
 			std::string ident = it.second->GetIdentHashBase64();
 			if (it.second->IsUpdated ())
 			{
@@ -655,8 +660,8 @@ namespace data
 					std::shared_ptr<RouterInfo::Buffer> buffer;
 					{
 						std::lock_guard<std::mutex> l(m_RouterInfosMutex); // possible collision between DeleteBuffer and Update
-						buffer = it.second->GetSharedBuffer ();
+						buffer = it.second->CopyBuffer ();
-						it.second->DeleteBuffer ();
+						it.second->ScheduleBufferToDelete ();
 					}
 					if (buffer && !it.second->IsUnreachable ()) // don't save bad router
 						saveToDisk.push_back(std::make_pair(ident, buffer));

libi2pd/RouterInfo.cpp

@@ -45,8 +45,9 @@ namespace data
 
 	RouterInfo::RouterInfo (const std::string& fullPath):
 		m_FamilyID (0), m_IsUpdated (false), m_IsUnreachable (false), m_IsFloodfill (false),
-		m_SupportedTransports (0),m_ReachableTransports (0), m_PublishedTransports (0),
+		m_IsBufferScheduledToDelete (false), m_SupportedTransports (0), 
-		m_Caps (0), m_Version (0), m_Congestion (eLowCongestion)
+		m_ReachableTransports (0), m_PublishedTransports (0), m_Caps (0), m_Version (0), 
+		m_Congestion (eLowCongestion)
 	{
 		m_Addresses = AddressesPtr(new Addresses ()); // create empty list
 		m_Buffer = RouterInfo::NewBuffer (); // always RouterInfo's
@@ -1140,6 +1141,7 @@ namespace data
 		if (len > m_Buffer->size ()) len = m_Buffer->size ();
 		memcpy (m_Buffer->data (), buf, len);
 		m_Buffer->SetBufferLen (len);
+		m_IsBufferScheduledToDelete = false;
 	}
 
 	std::shared_ptr<RouterInfo::Buffer> RouterInfo::CopyBuffer () const

libi2pd/RouterInfo.h

@@ -290,9 +290,11 @@ namespace data
 			const uint8_t * GetBuffer () const { return m_Buffer ? m_Buffer->data () : nullptr; };
 			const uint8_t * LoadBuffer (const std::string& fullPath); // load if necessary
 			size_t GetBufferLen () const { return m_Buffer ? m_Buffer->GetBufferLen () : 0; };
-			void DeleteBuffer () { m_Buffer = nullptr; };
+			void DeleteBuffer () { m_Buffer = nullptr; m_IsBufferScheduledToDelete = false; };
 			std::shared_ptr<Buffer> GetSharedBuffer () const { return m_Buffer; };	
 			std::shared_ptr<Buffer> CopyBuffer () const;
+			void ScheduleBufferToDelete () { m_IsBufferScheduledToDelete = false; };
+			bool IsBufferScheduledToDelete () const { return m_IsBufferScheduledToDelete; };
 
 			bool IsUpdated () const { return m_IsUpdated; };
 			void SetUpdated (bool updated) { m_IsUpdated = updated; };
@@ -354,7 +356,7 @@ namespace data
 #else		
 			AddressesPtr m_Addresses;
 #endif		
-			bool m_IsUpdated, m_IsUnreachable, m_IsFloodfill;
+			bool m_IsUpdated, m_IsUnreachable, m_IsFloodfill, m_IsBufferScheduledToDelete;
 			CompatibleTransports m_SupportedTransports, m_ReachableTransports, m_PublishedTransports;
 			uint8_t m_Caps;
 			char m_BandwidthCap;